Schistosomiasis, a neglected tropical disease (NTD), is one of the most prevalent parasitoses in the World. Certain freshwater snail species are the intermediate host in the life cycle of schistosome species. Controlling snails employing molluscicides is an effective, quick, and convenient intervention strategy to prevent the spread of Schistosoma species in endemic regions. Advances have been made in developing both synthetic molluscicides and molluscicides derived from plants. However, at present, the development of molluscicides is not adapted to the actual demand for snails and schistosoma controlling. We undertake a systematic review of exploitation and application of synthetic molluscicides and molluscicides derived from plants to combat intermediate host snails. The detailed molluscicidal activity, structure–activity relationship, structural feature, and possible mechanism of some molluscicides are also highlighted, which may afford an important reference for the design of new, more effective molluscicides with low environmental impact and realize the aim of controlling schistosome at transmission stages. Supplementary Information The online version contains supplementary material available at 10.1007/s00436-021-07288-4.

A new photocatalyst-free visible-light-enhanced strategy for the synthesis of pyrazolo­[1,5-a]­[1,3,5]­triazine-2,4-diamines via the formation of electron donor–acceptor (EDA) complexes is reported. The in situ generated pyrazolthiourea intermediates from 1H-pyrazol-3-amines and isothiocyanates undergo formal [4 + 2] annulation with 1,1,3,3-tetramethylguanidines (TMG) to deliver the corresponding products involved in three C–N bond formations in a one-pot protocol. The formation of EDA complex from pyrazolthiourea and TMG is confirmed by UV–vis spectroscopy and 1H NMR experiments. Moreover, this mild reaction proceeds in the absence of any external transition metals, oxidants, bases, and ligands. This efficient methodology for the synthesis of purine analogues pyrazolo­[1,5-a]­[1,3,5]­triazine-2,4-diamines provides potential synthetic applications in the field of drug research and development.

Hydrazonamides are fundamental building blocks in many pharmaceuticals and agricultural chemicals. Although contributions have been accomplished through multi-step reactions under harsh conditions, achieving high efficient synthetic strategy remains challenging. Considering...

A metal-and oxidant-free three-component desulfurization and deamination condensation of amidines, isothiocyanates, and hydrazines for the synthesis of structurally diverse fully substituted 1H-1,2,4-triazol-3-amines is described. The reaction proceeds without the requirement of any external catalysts, metals, ligands, or oxidants. This [2 + 1 + 2] cyclization strategy involves C−N and C−S bond cleavage and the formation of new C−N bonds in one pot. This transformation provides a series of full substituted 1H-1,2,4-triazol-3-amines with advantages of a broad substrates scope, mild reaction conditions, environmental friendliness, and easy gram-scale applications. The fluorescence and aggregation-induced emission (AIE) properties of selected products were further tested. These synthesized 1H-1,2,4-triazol-3-amines may be worth investigating for further applications in the fields of organic chemistry, medicinal chemistry, and optical materials.